As a kind of writing instrument, marker pen, especially the one using various solvent inks with low surface tension, is a widely used overlaying and writing instrument. Due to the low surface tension of the ink, it is prone to problems such as ink leakage, so the marker pen most uses the reservoir structure made of fiber, however such ink storage structure may have ink residue, and the ink consumption during writing is continuously decreased, resulting in inadequate stability in the writing process.
To solve the above problems, the patent CN01809151.2 discloses a writing instrument in which ink is stored in a cartridge partitioned by multiple walls, there are intercommunicating pores on each wall to retain the ink under the action of capillary force, and air-liquid exchange is achieved via the gap between the ink supplier and the wall.
Although the above patent can solve the problem of some reservoir writing instruments, since the gap between the ink supplier and the wall is actually filled with ink, in the writing process, since the ink in the cartridge is continuously absorbed into the ink supplier, and there will be two possibilities for the ink in the gap, absorbed into the ink supplier or remained in the gap, the change cannot be precisely controlled, the air-liquid exchange would be affected if the gap is slightly different during the actually manufactured. In addition, the physical and chemical indicators of ink also have a great influence on the air-liquid exchange, resulting in no guarantee of mass production stability.
In addition, the patent CN200480043409.6 discloses an ink supplier which stores ink by means of the partition wall projection being higher than the level of liquid stored in the said ink cartridge, and sets up an ink absorber at the tail of the ink supplier to provide the needed ink for writing.
In the above patent, since the partition wall is higher than the level of the ink in cartridge, the ink is less likely to leak, but the product must be laid horizontally and inverted, so that ink can infiltrate the ink supplier or the ink absorber at the tail. Therefore, there are major drawbacks in terms of ease of use.
The patent CN201310398639.5 discloses a liquid ink writing instrument which achieves air-liquid exchange by setting an air guiding device and an ink guiding device with connecting the said ink tube and the storage tube on the partition wall, and providing two solutions, one is a is similar to the patent CN01809151.2, the other is to realize by the separate air guide holes.
In the first solution of above patent, there are also two possibilities for the ink in the gap, which are absorbed into the ink supplier or remain in the gap, and the change cannot be accurately controlled; the problem of the second solution is also obvious, since the air guide hole is independent of the ink supplier, there is no direct connection between them, which easily causes an imbalance between the writing end and the intake end.
The patent CN201510887830.5 discloses a liquid ink partition, in which the ink storage structure formed between the outer circular wall and the bottom circular wall of the pen body is separated by the plurality of partition layers with at least one groove. The principle is to separate the ink in different compartments, to achieve ink discharge in the order of the compartments, and to improve the performance of leakage resistance.
The above patent also uses the gap between the ink supplier and the ink partition for air exchange. The ink supply and air exchange of the ink cartridge are realized by the same groove. Since the relatively independent passage cannot be available, the air exchange process is very complicated and difficult to control. In addition, the patent has the problem that it cannot be mass-produced in practice. The reason is that the volume occupied by the ink partition in the ink cartridge is large. If the ink partition is placed after the ink cartridge is filled first, the ink is prone to overflow and the air pressure in the ink cartridge is prone to rise. On the other hand, if the ink partition is placed first and then the ink cartridge is filled, the mass production cannot be achieved because the passage into each compartment is small and the filling time is too long.
The U.S. Pat. No. 6,659,671 discloses a liquid ink writing instrument which also achieves the air-liquid exchange by the gap between the ink supplier and the partition wall, resulting in difficult control of the process.
The patent CN200810097132.5 discloses a liquid ink writing instrument which realizes ink supply control in writing process by two independent air-ink guide tubes. Since two air-ink guide tubes independently adjust air inflow, there is a problem in the balance between them in use.
In summary, although various existing liquid ink writing tools can solve the shortcomings of some existing fiber reservoir writing tools, since in the above technical solutions, some use independent air guide passenger of the ink supplier, and some use the gaps of various shapes with the ink supplier to achieve air-liquid exchange, the precise control of the balance between ink and air pressure has not been achieved, so that various complicated and uncertain changes occur in the writing process, resulting in the system instability and lack of adaptability to ink.